Microscopic and molecular investigation of the parasite Ichthyophthirius multifiliis in rainbow trout in the fish breeding ponds of Rijab city.

Alikarami, Chiman; Kakekhani, Siyamak; Salimi, Behnam

doi:10.22092/ari.2026.367004.3329

Microscopic and molecular investigation of the parasite Ichthyophthirius multifiliis in rainbow trout in the fish breeding ponds of Rijab city.

Articles in Press

Document Type : Original Articles

Authors

¹ Graduated of veterinary medicine, Sanandaj Branch, Islamic Azad University , Sanandaj, Iran

² Assistant professor. Department of Pathobiology, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran

³ Department of Veterinary Clinical Sciences, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran

10.22092/ari.2026.367004.3329

Abstract

Rainbow trout is the most important farmed species of cold water fish that is densely farmed in the country's farms. Parasitic contamination is one of the factors that can endanger aquatic production. Active Fterius multifelis parasite is one of the most dangerous external parasites of fishes, especially juvenile freshwater fishes. I. multifiliis is a ciliated protozoan that can cause white spot disease. The purpose of this study is to determine microscopically and molecularly the parasite I. multifiliis in the rainbow trout fishes of Rajab fish breeding ponds. In this research that will take place in the city of Rajab, during the spring season of 1402, first, 100 samples of rainbow trout will be caught in several different fish breeding ponds and euthanized by MS-22. The samples included skin chips and skin mucus. The samples were stored in a freezer at -20 degrees Celsius. In order to investigate the prevalence and microscopic and molecular evaluation of I. multifiliis, PCR method was used. In this study, the accuracy of PCR detection was checked using sequencing technique. And finally, the following phylogenic tree was drawn for the studied sequences. In the microscopic examination by the wet slide method, ciliated parasites with horseshoe-like nuclei were observed. These parasites were similar to I. multifiliis. In the PCR test, the prevalence was estimated at 20%. The results of sequencing showed that the amplified DNA sequence was completely similar to the data recorded in the NCBI database. The studied sequences are very similar to each other in terms of genetic similarity and in the next step they are similar to Ark10, Ark5 and NY4 isolates respectively. . The studied sequences originate from one population or species. due to the possibility of parasitic infections and other pathogens due to the presence of native fish (as sensitive hosts or reserves) in the river and upstream fish farms and due to the relatively high prevalence of I.multifiliis parasites of foreign origin ; Compliance with health issues in rainbow trout farms is very important in order to prevent the entry of parasitic pathogens.

Keywords